TURNING SOLID METAL INTO A TRANSPARENT, HIGHLY REFRACTIVE FLUID is what happens when a 120-fsec laser pulse strikes a sample at the Institute for Laser- and Plasma Physics at the University of Essen. Researchers there make a slow-motion movie (with a frame every tenth of a picosecond) of laser ablation, the process (important in many industrial and surgical applications) in which laser light quickly heats and removes material from a solid. After the initial laser onslaught, the material in the affected area (about 300 microns across) is first pulled into a fluid state of high temperature (several 1000 K) and pressure (several tens of GPa) and then is carried away from the surface by hydrodynamic flow. The clue as to what this fluid is doing (temperature, index of refraction, etc.) during the expansion is the appearance of "Newton rings," the optical pattern set up when light rays reflecting from the ablating portion of the sample interfere with light reflecting from the remaining material in the back. These rings (never seen before) were remarkably similar for the whole range of metals and semiconductors tested, implying that some universal ablation mechanism was at work. (Klaus Sokolowski-Tinten et al., 6 July Physical Review Letters; see figureat Physics News Graphics; kst@ilp.physik.uni-essen.de.)